Labbing with Server DHCP and need WAN Access

Bloogen

When you are labbing and need to use DHCP on a VM server and still retain WAN access without stopping or interrupting a home routers DHCP, what is the best way? I am using VMWare Workstation 8 for most of my labs.

buzzkill

Easiest way is to add a bridged network adapter to your client VMs. That way your VM has one NIC on the private virtual network and the other would act like it was plugged into your router.

Alternatively add a bridged network adapter to your DHCP server, configure the RRAS role and set the DHCP settings to point the default gateway at your DHCP server.

MentholMoose

You can use any of the network types offered in VMware Workstation and configure your DHCP server and VMs accordingly.

1. In addition to whatever your VMs are currently using (perhaps a bridged network), add a second NIC attached to a host-only network to all VMs (e.g. the default vmnet1 network). Don't configure a default gateway for this network since there isn't one, and disable the built-in DHCP server for that network using the Virtual Network Editor.
2. Another option would be to configure all the NIC for the VMs to use a NAT network (e.g. vmnet8 ), disable the built-in DHCP server for it, and configure your DHCP server for that network. In this case, VMware Workstation would handle the routing for external traffic. You'd need to configure your DHCP server to assign the default gateway (you can find this in the network settings in the Virtual Network Editor).
3. Yet another option is to put all VM NICs on a network bridged to your home LAN (e.g. vmnet0) and configure it for the LAN. As long as it is assigning correct IPs and settings to clients on your LAN, it is probably won't cause a problem. When using two DHCP servers on a single network, to be extra careful you can configure them to hand out different IP address ranges (so if your router does 192.168.0.10-50, configure your lab DHCP server to do 192.168.0.51-60). To be even more careful, you can configure your DHCP server to only assign IPs to VMs (and not to other clients on the LAN), such as through DHCP reservations or MAC address filters. Your router may even have similar options. So for example, you could blacklist 00-50-56-*-*-* (VMware VMs) on your router, whitelist this on your DHCP server, and the result would be that your router would not offer DHCP to your VMs and your DHCP server would only offer DHCP to VMs, eliminating any chance of conflicts.

I don't think there is a "best" option. Personally I'd probably go with option 2, but option 3 is nice as well since it might force you to play around with some DHCP options that you otherwise wouldn't.